1. Field of the Invention
The present invention relates to a musical-tone-control apparatus that can control musical tones according to a performer's swing of a baton.
2. Prior Art
As is well known, conventional electronic keyboard instruments are designed to generate musical tones of desired tone pitches and tone colors by the operation of a keyboard or by the operation of various controllers with the hands or the feet. Operations for generating musical tones by the conventional instruments are thus limited to those controlled by the hands and the feet. Hence, the applicant has proposed a new musical-tone- control apparatus that can control musical tones by swinging a baton shown in FIG. 1A and 1B.
In FIG. 1A, numeral 1 designates a baton. It has grip 1a to be held in the hand of a performer, and rod 1b jointed to grip 1a. Rod 1b contains acceleration sensor 2 shown in FIG. 1B. Acceleration sensor 2 comprises support members 3 and 3, cantilever spring 4 fixed to support members 3 and 3 on one end, mass 5 of a predetermined weight mounted to the other end of cantilever spring 4, and strain gage 6 including piezoresistive strain-sensing elements such as piezoelectric plastic film for detecting deflection of cantilever spring 4. When a downward or an upward acceleration is given, cantilever spring 4, which is being deflected in the upward or downward direction as shown by the arrow, causes a signal proportional to the acceleration to develop from strain gage 6. Consequently, when a performer holds grip 1a with mark 1c upwards provided thereto, and swings baton 1 downwards or upwards, acceleration sensor 2 produces output signal Sg proportional to the intensity of the swing.
Output signal Sg is supplied to musical-tone-signal-generating circuit 6 shown in FIG. 2. Musical-tone-signal-generating circuit 6 generates a musical-tone signal of a tone pitch and/or tone volume corresponding to a peak of output signal Sg, and this signal drives speaker SP. Thus, the performer can control musical-tone signals by varying the intensity of swings. For example, the stronger baton 1 is swung, the higher the tone pitches become. The musical-tone-control apparatus described above is designed so that a musical tone is generated at the peak of output signal Sg of acceleration sensor 2 by judging the peak as an intensity of swing of baton 1. However, the apparatus has a disadvantage that the performer feels out of synchronism with the apparatus when he performs, because the generation of a musical tone is delayed a moment after he has completed a swing.
More specifically, when the performer swings baton 1 down from point A in FIG. 3, he feels that he has completed the swing at point C. In reality, however, baton 1 does not stop at point C, and reaches point D because of inertia. According to the movement of baton 1 from point A to D, the amplitude of output signal Sg of acceleration sensor 2 varies as shown in FIG. 4, having a peak value at the lowest point D. Consequently, if a musical tone is generated when the peak value Vmax is developed at point D, the generation of the musical tone is momentarily delayed, and the performer will note a considerable discrepancy between the time of swing completion and the generation of the musical tone.